CA2825540C - Waveguide-type polarization beam splitter exhibiting reduced temperature-related wavelength dependent variation of the polarization extinction ratio - Google Patents
Waveguide-type polarization beam splitter exhibiting reduced temperature-related wavelength dependent variation of the polarization extinction ratio Download PDFInfo
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- CA2825540C CA2825540C CA2825540A CA2825540A CA2825540C CA 2825540 C CA2825540 C CA 2825540C CA 2825540 A CA2825540 A CA 2825540A CA 2825540 A CA2825540 A CA 2825540A CA 2825540 C CA2825540 C CA 2825540C
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- 230000010287 polarization Effects 0.000 title claims abstract description 102
- 230000008033 biological extinction Effects 0.000 title abstract description 17
- 230000001419 dependent effect Effects 0.000 title description 2
- 230000001747 exhibiting effect Effects 0.000 title description 2
- 230000003287 optical effect Effects 0.000 claims abstract description 152
- 230000010363 phase shift Effects 0.000 claims description 10
- 239000000758 substrate Substances 0.000 claims description 10
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 239000004642 Polyimide Substances 0.000 claims description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 4
- 229920001721 polyimide Polymers 0.000 claims description 4
- 239000010453 quartz Substances 0.000 claims description 4
- 229910052710 silicon Inorganic materials 0.000 claims description 4
- 239000010703 silicon Substances 0.000 claims description 4
- 230000006866 deterioration Effects 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000013307 optical fiber Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/126—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind using polarisation effects
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12083—Constructional arrangements
- G02B2006/12116—Polariser; Birefringent
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B2006/12133—Functions
- G02B2006/1215—Splitter
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/27—Optical coupling means with polarisation selective and adjusting means
- G02B6/2753—Optical coupling means with polarisation selective and adjusting means characterised by their function or use, i.e. of the complete device
- G02B6/2793—Controlling polarisation dependent loss, e.g. polarisation insensitivity, reducing the change in polarisation degree of the output light even if the input polarisation state fluctuates
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
- G02B6/2808—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using a mixing element which evenly distributes an input signal over a number of outputs
- G02B6/2813—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using a mixing element which evenly distributes an input signal over a number of outputs based on multimode interference effect, i.e. self-imaging
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Integrated Circuits (AREA)
Abstract
Provided is a waveguide-type polarization beam splitter in which deterioration of a polarization extinction ratio due to temperature change and wavelength change is suppressed. A groove is formed to extend across the pair of optical waveguide arms and two quarter wave plates are provided in the groove to extend respectively across the arms. Polarization axes of a quarter wave plates are orthogonal to each other. A first optical coupler which gives a phase difference of 0° or 180° between coupled or split light beams and a second optical coupler which gives a phase difference of 900 or -90° between coupled or split light beams are used in combination.
Description
DESCRIPTION
WAVEGUIDE-TYPE POLARIZATION BEAM SPLITTER EXHIBITING REDUCED
TEMPERATURE-RELATED WAVELENGTH DEPENDENT VARIATION OF THE
POLARIZATION EXTINCTION RATIO
Technical Field [0001]
The present invention relates to a waveguide-type polarization beam splitter, and more specifically, to a waveguide-type polarization beam splitter which couples and splits polarized waves.
Background Art
WAVEGUIDE-TYPE POLARIZATION BEAM SPLITTER EXHIBITING REDUCED
TEMPERATURE-RELATED WAVELENGTH DEPENDENT VARIATION OF THE
POLARIZATION EXTINCTION RATIO
Technical Field [0001]
The present invention relates to a waveguide-type polarization beam splitter, and more specifically, to a waveguide-type polarization beam splitter which couples and splits polarized waves.
Background Art
[0002]
Polarized and multiplexed optical signals are increasingly used for large-capacity optical communications and importance of polarization beam splitters for coupling and splitting polarized waves is increasing. Particularly, a waveguide-type polarization beam splitter is attracting attention because the waveguide-type polarization beam splitter can be integrated with other waveguide-type devices such as a coupler, a delayed interferometer, and an optical hybrid. The waveguide-type polarization beam splitter generally achieves a polarization wave coupling-splitting function as follows. A phase difference of n is provided between a TE polarization and a TM polarization in a configuration of a Mach-Zehnder interferometer (MZI) and the phase difference of the TE polarization in the interferometer - la -, CA 02825540 2013-07-23 , . .
is set to 0 (or n) while the phase difference of the TM
polarization in the interferometer is set to it (or 0).
Polarized and multiplexed optical signals are increasingly used for large-capacity optical communications and importance of polarization beam splitters for coupling and splitting polarized waves is increasing. Particularly, a waveguide-type polarization beam splitter is attracting attention because the waveguide-type polarization beam splitter can be integrated with other waveguide-type devices such as a coupler, a delayed interferometer, and an optical hybrid. The waveguide-type polarization beam splitter generally achieves a polarization wave coupling-splitting function as follows. A phase difference of n is provided between a TE polarization and a TM polarization in a configuration of a Mach-Zehnder interferometer (MZI) and the phase difference of the TE polarization in the interferometer - la -, CA 02825540 2013-07-23 , . .
is set to 0 (or n) while the phase difference of the TM
polarization in the interferometer is set to it (or 0).
[0003]
Fig. 1 shows an example of a conventional waveguide-type polarization beam splitter. The conventional waveguide-type polarization beam splitter includes input optical waveguides 101a, 101b, a first optical coupler 102, a pair of waveguide arms 103, a groove 104 provided to extend across the waveguide arms 103, quarter wave plates 105a, 105b of angles of 0 and 90 which are inserted in the groove 104, a second optical coupler 106, and output optical waveguides 107a, 107b (see Patent Literature 1). Since the wave plates inserted in the respective arms give the phase difference between the polarized waves in this method, a polarization beam splitter excellent in temperature characteristics can be achieved.
Citation List Patent Literature
Fig. 1 shows an example of a conventional waveguide-type polarization beam splitter. The conventional waveguide-type polarization beam splitter includes input optical waveguides 101a, 101b, a first optical coupler 102, a pair of waveguide arms 103, a groove 104 provided to extend across the waveguide arms 103, quarter wave plates 105a, 105b of angles of 0 and 90 which are inserted in the groove 104, a second optical coupler 106, and output optical waveguides 107a, 107b (see Patent Literature 1). Since the wave plates inserted in the respective arms give the phase difference between the polarized waves in this method, a polarization beam splitter excellent in temperature characteristics can be achieved.
Citation List Patent Literature
[0004]
PTL 1: Japanese Patent Laid-Open No. H07-092326(1995) Summary of Invention Technical Problem
PTL 1: Japanese Patent Laid-Open No. H07-092326(1995) Summary of Invention Technical Problem
[0005]
However, the conventional configuration has a problem that wavelength dependence is large. In the configuration of Fig. 1, since directional couplers are used for the first optical coupler 102 and the second optical coupler 106, the wavelength dependence of the directional couplers occurs.
Moreover, since the quarter wave plates 105 give phases of 90 and -90 to the polarization TE and the polarization TM
orthogonal thereto, a delay portion of a quarter wavelength needs to be provided in the waveguide arm 103a or 103b for the operation of the polarization beam splitter. Since the delay portion has the wavelength dependency, the characteristics of the polarization beam splitter deteriorate.
However, the conventional configuration has a problem that wavelength dependence is large. In the configuration of Fig. 1, since directional couplers are used for the first optical coupler 102 and the second optical coupler 106, the wavelength dependence of the directional couplers occurs.
Moreover, since the quarter wave plates 105 give phases of 90 and -90 to the polarization TE and the polarization TM
orthogonal thereto, a delay portion of a quarter wavelength needs to be provided in the waveguide arm 103a or 103b for the operation of the polarization beam splitter. Since the delay portion has the wavelength dependency, the characteristics of the polarization beam splitter deteriorate.
[0006]
Fig. 2 is a view showing the wavelength characteristics of the conventional waveguide-type polarization beam splitter which is ideally manufactured. As is apparent from Fig. 2, even in the ideally-manufactured conventional waveguide-type polarization beam splitter, an extinction ratio deteriorates to a level equal to or below 25 dB in a wavelength range of 1.53 to 1.565 microns.
Fig. 2 is a view showing the wavelength characteristics of the conventional waveguide-type polarization beam splitter which is ideally manufactured. As is apparent from Fig. 2, even in the ideally-manufactured conventional waveguide-type polarization beam splitter, an extinction ratio deteriorates to a level equal to or below 25 dB in a wavelength range of 1.53 to 1.565 microns.
[0007]
Fig. 3 shows a histogram of the conventional waveguide-type polarization beam splitter in a case where the manufacturing tolerance is considered. Even in a case where the manufacturing tolerance is considered, the extinction ratio of a port 1 is equal to or below 25 dB.
Fig. 3 shows a histogram of the conventional waveguide-type polarization beam splitter in a case where the manufacturing tolerance is considered. Even in a case where the manufacturing tolerance is considered, the extinction ratio of a port 1 is equal to or below 25 dB.
[0008]
The present invention has been made in view of the above problems and an object thereof is to provide a waveguide-type polarization beam splitter in which deterioration of a polarization extinction ratio due to temperature change and wavelength change is suppressed.
Solution to Problem
The present invention has been made in view of the above problems and an object thereof is to provide a waveguide-type polarization beam splitter in which deterioration of a polarization extinction ratio due to temperature change and wavelength change is suppressed.
Solution to Problem
[0009]
According to one aspect, there is provided a waveguide-type polarization beam splitter formed on a substrate, characterized in that the waveguide-type polarization beam splitter comprises: one or two input optical waveguides; a first optical coupler optically coupled to the one or two input optical waveguides and having one input and two outputs or two inputs and two outputs; a pair of optical waveguide arms optically coupled to the outputs of the first optical coupler, wherein the pair of optical waveguide arms includes a first optical waveguide arm and a second optical waveguide arm; and a second optical coupler optically coupled to the pair of optical waveguide arms and having two inputs and one output or two inputs and two outputs, wherein a groove is provided to extend across the pair of optical waveguide arms, two quarter wave plates are inserted in the groove to extend respectively across the pair of optical waveguide arms, and polarization axes of the respective two quarter wave plates are orthogonal to each other, one of the first optical coupler and the second optical coupler is an optical coupler which gives a phase shift of about 90 or about -90 between coupled or split light beams, and another one of the first optical coupler and the second optical coupler is an optical coupler which gives a phase shift of about 0 or about 180 between coupled or split light beams, and a length of the first optical waveguide arm extending between the first and second optical couplers equals to a length of the second optical waveguide arm extending between the first and second couplers.
According to one aspect, there is provided a waveguide-type polarization beam splitter formed on a substrate, characterized in that the waveguide-type polarization beam splitter comprises: one or two input optical waveguides; a first optical coupler optically coupled to the one or two input optical waveguides and having one input and two outputs or two inputs and two outputs; a pair of optical waveguide arms optically coupled to the outputs of the first optical coupler, wherein the pair of optical waveguide arms includes a first optical waveguide arm and a second optical waveguide arm; and a second optical coupler optically coupled to the pair of optical waveguide arms and having two inputs and one output or two inputs and two outputs, wherein a groove is provided to extend across the pair of optical waveguide arms, two quarter wave plates are inserted in the groove to extend respectively across the pair of optical waveguide arms, and polarization axes of the respective two quarter wave plates are orthogonal to each other, one of the first optical coupler and the second optical coupler is an optical coupler which gives a phase shift of about 90 or about -90 between coupled or split light beams, and another one of the first optical coupler and the second optical coupler is an optical coupler which gives a phase shift of about 0 or about 180 between coupled or split light beams, and a length of the first optical waveguide arm extending between the first and second optical couplers equals to a length of the second optical waveguide arm extending between the first and second couplers.
[0010]
- 4a -A second aspect of the present invention is the first aspect characterized in that the optical coupler which gives the phase shift of about 00 or about 180 between coupled or split light beams is any one of a Y-branch coupler, a multimode interference optical coupler having one input and two outputs, a multimode interference optical coupler having two inputs and one output, and an X-branch coupler.
- 4a -A second aspect of the present invention is the first aspect characterized in that the optical coupler which gives the phase shift of about 00 or about 180 between coupled or split light beams is any one of a Y-branch coupler, a multimode interference optical coupler having one input and two outputs, a multimode interference optical coupler having two inputs and one output, and an X-branch coupler.
[0011]
A third aspect of the present invention is the first or second aspect characterized in that the optical coupler which gives the phase shift of about 90 or about -90 between coupled or split light beams is a multimode interference optical coupler having two inputs and two outputs or a directional coupler.
A third aspect of the present invention is the first or second aspect characterized in that the optical coupler which gives the phase shift of about 90 or about -90 between coupled or split light beams is a multimode interference optical coupler having two inputs and two outputs or a directional coupler.
[0012]
A fourth aspect of the present invention is any one of the first to third aspects characterized in that the angles of the polarization axes of the two quarter wave plates respectively form angles of 0 and 90 with respect to a substrate plane of a waveguide.
A fourth aspect of the present invention is any one of the first to third aspects characterized in that the angles of the polarization axes of the two quarter wave plates respectively form angles of 0 and 90 with respect to a substrate plane of a waveguide.
[0013]
A fifth aspect of the present invention is any one of the first to fourth aspects characterized in that each of the two quarter wave plates is a polyimide wave plate.
A fifth aspect of the present invention is any one of the first to fourth aspects characterized in that each of the two quarter wave plates is a polyimide wave plate.
[0014]
A sixth aspect of the present invention is any one of the first to fifth aspects characterized in that the waveguide-type polarization beam splitter further comprises tapered portions before and after the groove.
A sixth aspect of the present invention is any one of the first to fifth aspects characterized in that the waveguide-type polarization beam splitter further comprises tapered portions before and after the groove.
[0015]
A seventh aspect of the present invention is any one of the first to sixth aspects characterized in that the waveguide-type polarization beam splitter further comprises waveguide lenses before and after the groove.
A seventh aspect of the present invention is any one of the first to sixth aspects characterized in that the waveguide-type polarization beam splitter further comprises waveguide lenses before and after the groove.
[0016]
An eighth aspect of the present invention is any one of the first to seventh aspects characterized in that each of the optical waveguides is a quartz-based optical waveguide formed on a silicon substrate.
Advantageous Effects of Invention
An eighth aspect of the present invention is any one of the first to seventh aspects characterized in that each of the optical waveguides is a quartz-based optical waveguide formed on a silicon substrate.
Advantageous Effects of Invention
[0017]
The groove is provided to extend across both of the pair of optical waveguide arms forming a MZI, the two quarter wave plates are inserted in the groove to extend respectively across the pair of optical waveguide arms, quarter wave plates whose polarization axes are orthogonal to each other are used as the two quarter wave plates, and the optical coupler which gives the phase shift of about 90 or about -90 and the optical coupler which gives the phase shift of about 0 or about 180 are used in combination as the optical couplers. This can provide a waveguide-type polarization beam splitter in which deterioration of the polarization extinction ratio due to wavelength change and temperature change is suppressed.
Brief Description of Drawings
The groove is provided to extend across both of the pair of optical waveguide arms forming a MZI, the two quarter wave plates are inserted in the groove to extend respectively across the pair of optical waveguide arms, quarter wave plates whose polarization axes are orthogonal to each other are used as the two quarter wave plates, and the optical coupler which gives the phase shift of about 90 or about -90 and the optical coupler which gives the phase shift of about 0 or about 180 are used in combination as the optical couplers. This can provide a waveguide-type polarization beam splitter in which deterioration of the polarization extinction ratio due to wavelength change and temperature change is suppressed.
Brief Description of Drawings
[0018]
[Fig. 1] Fig. 1 is a view showing a conventional waveguide-type polarization beam splitter;
[Fig. 2] Fig. 2 is a graph showing wavelength dependence of a polarization extinction ratio of the conventional waveguide-type polarization beam splitter;
[Fig. 3] Fig. 3 is a histogram showing the polarization extinction ratio of the conventional waveguide-type polarization beam splitter;
[Fig. 4] Fig. 4 is a view showing a waveguide-type polarization beam splitter of a first embodiment;
[Fig. 5] Fig. 5 is a cross-sectional view taken along the V-V
line of Fig. 4;
[Fig. 6] Fig. 6 is a graph showing wavelength dependence of a polarization extinction ratio of a waveguide-type polarization beam splitter in the first embodiment;
[Fig. 7] Fig. 7 is a histogram showing the polarization extinction ratio of the waveguide-type polarization beam splitter in the first embodiment;
[Fig. 8] Fig. 8 is a view showing a modification of the waveguide-type polarization beam splitter of the first embodiment;
[Fig. 9] Fig. 9 is a view showing a waveguide-type polarization beam splitter of a second embodiment;
[Fig. 10] Fig. 10 is a cross-sectional view taken along the X-X line of Fig. 9;
[Fig. 11] Fig. 11 is a view showing wavelength dependence of a polarization extinction ratio of the waveguide-type polarization beam splitter in the second embodiment; and [Fig. 12] Fig. 12 is a histogram showing the polarization extinction ratio of the waveguide-type polarization beam splitter in the second embodiment.
Description of Embodiments
[Fig. 1] Fig. 1 is a view showing a conventional waveguide-type polarization beam splitter;
[Fig. 2] Fig. 2 is a graph showing wavelength dependence of a polarization extinction ratio of the conventional waveguide-type polarization beam splitter;
[Fig. 3] Fig. 3 is a histogram showing the polarization extinction ratio of the conventional waveguide-type polarization beam splitter;
[Fig. 4] Fig. 4 is a view showing a waveguide-type polarization beam splitter of a first embodiment;
[Fig. 5] Fig. 5 is a cross-sectional view taken along the V-V
line of Fig. 4;
[Fig. 6] Fig. 6 is a graph showing wavelength dependence of a polarization extinction ratio of a waveguide-type polarization beam splitter in the first embodiment;
[Fig. 7] Fig. 7 is a histogram showing the polarization extinction ratio of the waveguide-type polarization beam splitter in the first embodiment;
[Fig. 8] Fig. 8 is a view showing a modification of the waveguide-type polarization beam splitter of the first embodiment;
[Fig. 9] Fig. 9 is a view showing a waveguide-type polarization beam splitter of a second embodiment;
[Fig. 10] Fig. 10 is a cross-sectional view taken along the X-X line of Fig. 9;
[Fig. 11] Fig. 11 is a view showing wavelength dependence of a polarization extinction ratio of the waveguide-type polarization beam splitter in the second embodiment; and [Fig. 12] Fig. 12 is a histogram showing the polarization extinction ratio of the waveguide-type polarization beam splitter in the second embodiment.
Description of Embodiments
[0019]
Embodiments of the present invention are described below with reference to the drawings.
Embodiments of the present invention are described below with reference to the drawings.
[0020]
(First Embodiment) Fig. 4 shows a waveguide-type polarization beam splitter of a first embodiment. The waveguide-type polarization beam splitter includes: one input optical waveguide 11; a first optical coupler 12 which is optically coupled to the one input optical waveguide 11 and which has one input and two outputs;
a pair of optical waveguide arms 13a and 13b which is optically coupled to the respective outputs of the first optical coupler;
and a second optical coupler 18 which is optically coupled to the pair of optical waveguide arms 13a and 13b and which has two inputs and two outputs. The first optical coupler 12, the pair of optical waveguide arms 13, and the second optical coupler 18 form a MZI.
(First Embodiment) Fig. 4 shows a waveguide-type polarization beam splitter of a first embodiment. The waveguide-type polarization beam splitter includes: one input optical waveguide 11; a first optical coupler 12 which is optically coupled to the one input optical waveguide 11 and which has one input and two outputs;
a pair of optical waveguide arms 13a and 13b which is optically coupled to the respective outputs of the first optical coupler;
and a second optical coupler 18 which is optically coupled to the pair of optical waveguide arms 13a and 13b and which has two inputs and two outputs. The first optical coupler 12, the pair of optical waveguide arms 13, and the second optical coupler 18 form a MZI.
[0021]
In the waveguide-type polarization beam splitter of the embodiment, a groove 15 is formed to extend across the pair of optical waveguide arms 13a, 13b and two quarter wave plates 16a, 16b are provided in the groove 15 to extend across the arms 13a, 13b, respectively. Quarter wave plates whose polarization axes are orthogonal to each other are used as the two quarter wave plates 16a, 16b. In such a configuration, the two arms 13a, 13b, including the inserted wave plates, are completely symmetric to each other except in the directions of the polarization axes. Accordingly, temperature dependence is small.
In the waveguide-type polarization beam splitter of the embodiment, a groove 15 is formed to extend across the pair of optical waveguide arms 13a, 13b and two quarter wave plates 16a, 16b are provided in the groove 15 to extend across the arms 13a, 13b, respectively. Quarter wave plates whose polarization axes are orthogonal to each other are used as the two quarter wave plates 16a, 16b. In such a configuration, the two arms 13a, 13b, including the inserted wave plates, are completely symmetric to each other except in the directions of the polarization axes. Accordingly, temperature dependence is small.
[0022]
Moreover, a Y-branch coupler which gives a phase difference of 0 between light beams to be outputted to the optical waveguide arms 13a and 13b is used as the first optical coupler 12. Furthermore, a multimode interference (MMI) coupler which gives, respectively to light beams to be outputted to output ports 19a and 19b, phase differences of about 90 and about -90 with respect to light inputs respectively from the waveguide arms 13a and 13b and which has two inputs and two outputs (2x2) is used as the second optical coupler 18. Using the optical coupler which gives the phase difference of 0 or 180 between the coupled and split light beams and the optical coupler which gives the phase difference of 90 or -90 between the coupled and split light beams in combination can make the respective lengths of the waveguide arms 13a and 13b coincide with each other. Accordingly, there is no need to use a delay portion having wavelength dependence and the wavelength dependence is thus reduced.
Moreover, a Y-branch coupler which gives a phase difference of 0 between light beams to be outputted to the optical waveguide arms 13a and 13b is used as the first optical coupler 12. Furthermore, a multimode interference (MMI) coupler which gives, respectively to light beams to be outputted to output ports 19a and 19b, phase differences of about 90 and about -90 with respect to light inputs respectively from the waveguide arms 13a and 13b and which has two inputs and two outputs (2x2) is used as the second optical coupler 18. Using the optical coupler which gives the phase difference of 0 or 180 between the coupled and split light beams and the optical coupler which gives the phase difference of 90 or -90 between the coupled and split light beams in combination can make the respective lengths of the waveguide arms 13a and 13b coincide with each other. Accordingly, there is no need to use a delay portion having wavelength dependence and the wavelength dependence is thus reduced.
[0023]
In the embodiment, the Y-branch coupler is used as the optical coupler which gives the phase difference of about 0 or about 1800 between the coupled and split light beams. This is because a small and low-loss waveguide-type polarization beam splitter can be provided by using the Y-branch coupler.
However, the present invention is not limited to this example.
Any optical coupler, such as an MMI coupler having one input and two outputs (1x2) or an adiabatic X-branch coupler, which gives the phase difference of 00 or 180 between the coupled and split light beams can be used as a matter of course.
In the embodiment, the Y-branch coupler is used as the optical coupler which gives the phase difference of about 0 or about 1800 between the coupled and split light beams. This is because a small and low-loss waveguide-type polarization beam splitter can be provided by using the Y-branch coupler.
However, the present invention is not limited to this example.
Any optical coupler, such as an MMI coupler having one input and two outputs (1x2) or an adiabatic X-branch coupler, which gives the phase difference of 00 or 180 between the coupled and split light beams can be used as a matter of course.
[0024]
In the embodiment, a 2x2 MMI coupler is used as an optical coupler which gives the phase difference of about 90 or about -90 between the coupled and split light beams. This is because a polarization beam splitter having small wavelength dependence and excellent manufacturing tolerance can be provided by using the 2x2 MMI coupler. However, the present invention is not limited to this example. Any coupler, such as a directional coupler, which gives the phase difference of about 90 or about -90 between the coupled and split light beams can be used as a matter of course.
In the embodiment, a 2x2 MMI coupler is used as an optical coupler which gives the phase difference of about 90 or about -90 between the coupled and split light beams. This is because a polarization beam splitter having small wavelength dependence and excellent manufacturing tolerance can be provided by using the 2x2 MMI coupler. However, the present invention is not limited to this example. Any coupler, such as a directional coupler, which gives the phase difference of about 90 or about -90 between the coupled and split light beams can be used as a matter of course.
[0025]
In the embodiment, the waveguide beam splitter having one input and two outputs is formed by using the Y-branch coupler having one input and two outputs on the input side and by using the MMI coupler having two inputs and two outputs on the output side. However, it is possible to reverse the input and the output and configure a polarization beam combiner having two inputs and one output by using the MMI optical coupler having two inputs and two outputs on the input side and by using the Y-branch coupler having two inputs and one output on the output side, as a matter of course.
In the embodiment, the waveguide beam splitter having one input and two outputs is formed by using the Y-branch coupler having one input and two outputs on the input side and by using the MMI coupler having two inputs and two outputs on the output side. However, it is possible to reverse the input and the output and configure a polarization beam combiner having two inputs and one output by using the MMI optical coupler having two inputs and two outputs on the input side and by using the Y-branch coupler having two inputs and one output on the output side, as a matter of course.
[0026]
Each of the arms 13a, 13b included in the pair of optical waveguide arms 13 can be, for example, a silica-based optical waveguide having a relative index difference of 1.5% on a silicon substrate. This optical waveguide has such advantages that a connection loss with an optical fiber is less than 0.6 dB/point and the mass productivity and controllability are excellent.
Each of the arms 13a, 13b included in the pair of optical waveguide arms 13 can be, for example, a silica-based optical waveguide having a relative index difference of 1.5% on a silicon substrate. This optical waveguide has such advantages that a connection loss with an optical fiber is less than 0.6 dB/point and the mass productivity and controllability are excellent.
[0027]
The quarter wave plates 16a, 16b can be manufactured from polyimide. Since the quarter wave plates 16a, 16b made of polyimide are thin, the groove 15 in which the quarter wave plates 16a, 16b are inserted can have such a narrow width as 20 pm, for example. Setting the angles of the polarization axes to 0' and 90 with respect to the line perpendicular to a plane on which the pair of optical waveguide arms 13a and 13b are formed causes the separated polarization waves to become linear polarization waves and handling is facilitated.
The quarter wave plates 16a, 16b can be manufactured from polyimide. Since the quarter wave plates 16a, 16b made of polyimide are thin, the groove 15 in which the quarter wave plates 16a, 16b are inserted can have such a narrow width as 20 pm, for example. Setting the angles of the polarization axes to 0' and 90 with respect to the line perpendicular to a plane on which the pair of optical waveguide arms 13a and 13b are formed causes the separated polarization waves to become linear polarization waves and handling is facilitated.
[0028]
A tapered portion may be provided in each of waveguide portions before and after the groove 15 to reduce an excess loss in the groove 15. The width of a terminal end of the tapered portion is preferably 10 m or more.
A tapered portion may be provided in each of waveguide portions before and after the groove 15 to reduce an excess loss in the groove 15. The width of a terminal end of the tapered portion is preferably 10 m or more.
[0029]
Fig. 5 shows a cross-sectional view taken along the V-V
line of Fig. 4. The two arms 13a, 13b are formed on a substrate and the quarter wave plates 16a, 16b are provided to extend across cores of the respective arms 13a, 13b.
Fig. 5 shows a cross-sectional view taken along the V-V
line of Fig. 4. The two arms 13a, 13b are formed on a substrate and the quarter wave plates 16a, 16b are provided to extend across cores of the respective arms 13a, 13b.
[0030]
In contrast to the example shown in Fig. 2, in the waveguide-type polarization beam splitter of the embodiment, the wavelength dependence of the polarization extinction ratio is drastically reduced as shown in Fig. 6.
In contrast to the example shown in Fig. 2, in the waveguide-type polarization beam splitter of the embodiment, the wavelength dependence of the polarization extinction ratio is drastically reduced as shown in Fig. 6.
[0031]
Moreover, in contrast to the example shown in Fig. 3, in the waveguide-type polarization beam splitter of the embodiment, the polarization extinction ratio of 30dB or more is secured as shown in Fig. 7 in a case where the manufacturing tolerance is considered.
Moreover, in contrast to the example shown in Fig. 3, in the waveguide-type polarization beam splitter of the embodiment, the polarization extinction ratio of 30dB or more is secured as shown in Fig. 7 in a case where the manufacturing tolerance is considered.
[0032]
(Modification of the First Embodiment) Fig. 8 shows a waveguide-type polarization beam splitter of a modification of the first embodiment. The waveguide-type polarization beam splitter includes: two input optical waveguides 11a, lib; a first optical coupler 12 which is optically coupled to the two input optical waveguides 11a, llb , CA 02825540 2013-07-23 , , and which has two inputs and two outputs; a pair of optical waveguide arms 13 which is optically coupled to the respective outputs of the first optical coupler; and a second optical coupler 18 which is optically coupled to the pair of optical waveguide arms 13 and which has two inputs and two outputs. The first optical coupler 12, the pair of optical waveguide arms 13, and the second optical coupler 18 form a MZI.
(Modification of the First Embodiment) Fig. 8 shows a waveguide-type polarization beam splitter of a modification of the first embodiment. The waveguide-type polarization beam splitter includes: two input optical waveguides 11a, lib; a first optical coupler 12 which is optically coupled to the two input optical waveguides 11a, llb , CA 02825540 2013-07-23 , , and which has two inputs and two outputs; a pair of optical waveguide arms 13 which is optically coupled to the respective outputs of the first optical coupler; and a second optical coupler 18 which is optically coupled to the pair of optical waveguide arms 13 and which has two inputs and two outputs. The first optical coupler 12, the pair of optical waveguide arms 13, and the second optical coupler 18 form a MZI.
[0033]
In the waveguide-type polarization beam splitter of the embodiment, a groove 15 is formed to extend across both of the paired optical waveguide arms 13a, 13b and two quarter wave plates 16a, 16b are provided in the groove 15 to extend across the arms 13a, 13b, respectively. Quarter wave plates whose polarization axes are orthogonal to each other are used as the two quarter wave plates 16a, 16b. In such a configuration, the two arms 13a, 13b, including the inserted wave plates, are completely symmetric to each other except in the directions of the polarization axes. Accordingly, the temperature dependence is reduced.
In the waveguide-type polarization beam splitter of the embodiment, a groove 15 is formed to extend across both of the paired optical waveguide arms 13a, 13b and two quarter wave plates 16a, 16b are provided in the groove 15 to extend across the arms 13a, 13b, respectively. Quarter wave plates whose polarization axes are orthogonal to each other are used as the two quarter wave plates 16a, 16b. In such a configuration, the two arms 13a, 13b, including the inserted wave plates, are completely symmetric to each other except in the directions of the polarization axes. Accordingly, the temperature dependence is reduced.
[0034]
Moreover, an adiabatic X-branch coupler which gives a phase difference of about 0 and about 180 between light beams to be outputted to the optical waveguide arms 13a and 13b is used as the first optical coupler 12. Furthermore, a multimode interference (MMI) coupler which gives, respectively to light beams to be outputted to output ports 19a and 19b, phase differences of about 90 and about -90 with respect to light inputs respectively from the waveguide arms 13a and 13b and which has two inputs and two outputs (2x2) is used as the second optical coupler 18. Using the optical coupler which gives the phase difference of about 0 or about 1800 between the coupled and split light beams and the optical coupler which gives the phase difference of about 90 or about -900 between the coupled and split light beams in combination can make the respective lengths of the waveguide arms 13a and 13b coincide with each other. Accordingly, there is no need to use a delay portion having wavelength dependence and the wavelength dependence is thus reduced.
Moreover, an adiabatic X-branch coupler which gives a phase difference of about 0 and about 180 between light beams to be outputted to the optical waveguide arms 13a and 13b is used as the first optical coupler 12. Furthermore, a multimode interference (MMI) coupler which gives, respectively to light beams to be outputted to output ports 19a and 19b, phase differences of about 90 and about -90 with respect to light inputs respectively from the waveguide arms 13a and 13b and which has two inputs and two outputs (2x2) is used as the second optical coupler 18. Using the optical coupler which gives the phase difference of about 0 or about 1800 between the coupled and split light beams and the optical coupler which gives the phase difference of about 90 or about -900 between the coupled and split light beams in combination can make the respective lengths of the waveguide arms 13a and 13b coincide with each other. Accordingly, there is no need to use a delay portion having wavelength dependence and the wavelength dependence is thus reduced.
[0035]
A parabolic optical waveguide may be provided in each of waveguide portions before and after the groove 15 to reduce an excess loss in the groove 15. The width of a terminal end of the parabolic optical waveguide is preferably 10 pm or more.
A parabolic optical waveguide may be provided in each of waveguide portions before and after the groove 15 to reduce an excess loss in the groove 15. The width of a terminal end of the parabolic optical waveguide is preferably 10 pm or more.
[0036]
Even in such a configuration, the waveguide-type polarization beam splitter having small wavelength dependence and small temperature dependence can be provided.
Even in such a configuration, the waveguide-type polarization beam splitter having small wavelength dependence and small temperature dependence can be provided.
[0037]
(Second Embodiment) Fig. 9 shows a waveguide-type polarization beam splitter of a second embodiment. The waveguide-type polarization beam splitter includes: one input optical waveguide 11; a first optical coupler 12 which is optically coupled to the one input optical waveguide 11 and which has one input and two outputs;
, CA 02825540 2013-07-23 , . , a pair of optical waveguide arms 13 (13a and 13b) which are optically coupled to the respective outputs of the first optical coupler; and a second optical coupler 18 which is optically coupled to the pair of optical waveguide arms 13a and 13b and which has two inputs and two outputs. The first optical coupler 12, the pair of optical waveguide arms 13, and the second optical coupler 18 form a MZI.
(Second Embodiment) Fig. 9 shows a waveguide-type polarization beam splitter of a second embodiment. The waveguide-type polarization beam splitter includes: one input optical waveguide 11; a first optical coupler 12 which is optically coupled to the one input optical waveguide 11 and which has one input and two outputs;
, CA 02825540 2013-07-23 , . , a pair of optical waveguide arms 13 (13a and 13b) which are optically coupled to the respective outputs of the first optical coupler; and a second optical coupler 18 which is optically coupled to the pair of optical waveguide arms 13a and 13b and which has two inputs and two outputs. The first optical coupler 12, the pair of optical waveguide arms 13, and the second optical coupler 18 form a MZI.
[0038]
In the waveguide-type polarization beam splitter of the embodiment, a groove 15 is formed to extend across the pair of optical waveguide arms 13a, 13b and two quarter wave plates 16a, 16b are provided in the groove 15 to extend across the arms 13a, 13b, respectively. Quarter wave plates whose polarization axes are orthogonal to each other are used as the two quarter wave plates 16a, 16b. In such a configuration, the two arms 13a, 13b, including the inserted wave plates, are completely symmetric to each other except in the directions of the polarization axes. Accordingly, the temperature dependence is reduced.
In the waveguide-type polarization beam splitter of the embodiment, a groove 15 is formed to extend across the pair of optical waveguide arms 13a, 13b and two quarter wave plates 16a, 16b are provided in the groove 15 to extend across the arms 13a, 13b, respectively. Quarter wave plates whose polarization axes are orthogonal to each other are used as the two quarter wave plates 16a, 16b. In such a configuration, the two arms 13a, 13b, including the inserted wave plates, are completely symmetric to each other except in the directions of the polarization axes. Accordingly, the temperature dependence is reduced.
[0039]
Moreover, a MMI coupler which gives a phase difference of 00 between light beams to be outputted to the optical waveguide arms 13a and 13b and which has one input and two outputs (1x2) is used as the first optical coupler 12. Furthermore, a directional coupler which gives, respectively to light beams to be outputted to output ports 19a and 19b, phase differences of about 90 and about -90 with respect to light inputs respectively from the waveguide arms 13a and 13b and which has two inputs and two outputs is used as the second optical coupler 18. Using the optical coupler which gives the phase difference of about 00 or about 180 between the coupled and split light beams and the optical coupler which gives the phase difference of about 90 or about -90 between the coupled and split light beams in combination can make the respective lengths of the waveguide arms 13a and 13b coincide with each other.
Accordingly, there is no need to use a delay portion having wavelength dependence and the wavelength dependence is thus reduced.
Moreover, a MMI coupler which gives a phase difference of 00 between light beams to be outputted to the optical waveguide arms 13a and 13b and which has one input and two outputs (1x2) is used as the first optical coupler 12. Furthermore, a directional coupler which gives, respectively to light beams to be outputted to output ports 19a and 19b, phase differences of about 90 and about -90 with respect to light inputs respectively from the waveguide arms 13a and 13b and which has two inputs and two outputs is used as the second optical coupler 18. Using the optical coupler which gives the phase difference of about 00 or about 180 between the coupled and split light beams and the optical coupler which gives the phase difference of about 90 or about -90 between the coupled and split light beams in combination can make the respective lengths of the waveguide arms 13a and 13b coincide with each other.
Accordingly, there is no need to use a delay portion having wavelength dependence and the wavelength dependence is thus reduced.
[0040]
In the embodiment, the MMI optical coupler of 1x2 is used as the optical coupler which gives the phase difference of 0 between the coupled and split light beams. However, the invention is not limited to this example. Any optical coupler, such as an adiabatic X-branch optical coupler or a lattice optical circuit including Mach-Zehnder interferometers connected in cascade, which gives the phase difference of 0 or 180 between the coupled and split light beams can be used, as a matter of course.
In the embodiment, the MMI optical coupler of 1x2 is used as the optical coupler which gives the phase difference of 0 between the coupled and split light beams. However, the invention is not limited to this example. Any optical coupler, such as an adiabatic X-branch optical coupler or a lattice optical circuit including Mach-Zehnder interferometers connected in cascade, which gives the phase difference of 0 or 180 between the coupled and split light beams can be used, as a matter of course.
[0041]
In the embodiment, the directional coupler is used as the optical coupler which gives the phase difference of about 90 or about -90 between the coupled and split light beams. This is because a polarization beam, splitter having a small loss can be provided by using the directional coupler. However, the present invention is not limited to this example. Any coupler, such as a MMI coupler, which gives the phase difference of about 90 or about -90 between coupled and split light beams can be used as a matter of course.
In the embodiment, the directional coupler is used as the optical coupler which gives the phase difference of about 90 or about -90 between the coupled and split light beams. This is because a polarization beam, splitter having a small loss can be provided by using the directional coupler. However, the present invention is not limited to this example. Any coupler, such as a MMI coupler, which gives the phase difference of about 90 or about -90 between coupled and split light beams can be used as a matter of course.
[0042]
In the embodiment, the polarization beam splitter having two inputs and two outputs is formed by using the MMI optical coupler having one input and two outputs on the input side and by using the directional coupler having two inputs and two outputs on the output side. However, it is possible to reverse the input and the output and configure a polarization beam combiner having two inputs and one output by using the directional coupler having two inputs and two outputs on the input side and by using the MMI optical coupler having two inputs and one output on the output side, as a matter of course.
In the embodiment, the polarization beam splitter having two inputs and two outputs is formed by using the MMI optical coupler having one input and two outputs on the input side and by using the directional coupler having two inputs and two outputs on the output side. However, it is possible to reverse the input and the output and configure a polarization beam combiner having two inputs and one output by using the directional coupler having two inputs and two outputs on the input side and by using the MMI optical coupler having two inputs and one output on the output side, as a matter of course.
[0043]
Each of the arms 13a, 13b included in the pair of optical waveguide arms 13 can be, for example, a silica-based optical waveguide having a relative index difference of 1.5% on a silicon substrate. This optical waveguide has such advantages that a connection loss with an optical fiber is less than 0.6 dB/point and the mass productivity and controllability are excellent.
Each of the arms 13a, 13b included in the pair of optical waveguide arms 13 can be, for example, a silica-based optical waveguide having a relative index difference of 1.5% on a silicon substrate. This optical waveguide has such advantages that a connection loss with an optical fiber is less than 0.6 dB/point and the mass productivity and controllability are excellent.
[0044]
The quarter wave plates 16a, 16b can be manufactured from crystalline quartz. The crystalline quartz has such characteristics that a wave plate having high stiffness and free of problems such as bending and warping can be provided and controllability is improved. Setting the angles of the polarization axes to 45 and -45 with respect to a line perpendicular to a plane on which the pair of optical waveguide arms 13a and 13b are formed allows the same type of wave plates to be inserted in different directions. Accordingly, there is an advantage that the number of parts can be reduced.
The quarter wave plates 16a, 16b can be manufactured from crystalline quartz. The crystalline quartz has such characteristics that a wave plate having high stiffness and free of problems such as bending and warping can be provided and controllability is improved. Setting the angles of the polarization axes to 45 and -45 with respect to a line perpendicular to a plane on which the pair of optical waveguide arms 13a and 13b are formed allows the same type of wave plates to be inserted in different directions. Accordingly, there is an advantage that the number of parts can be reduced.
[0045]
A parabolic optical waveguide 17 may be provided in each of waveguide portions before and after the groove 15 to reduce an excess loss in the groove 15. The width of a terminal end of the parabolic optical waveguide is preferably 10 jim or more.
A parabolic optical waveguide 17 may be provided in each of waveguide portions before and after the groove 15 to reduce an excess loss in the groove 15. The width of a terminal end of the parabolic optical waveguide is preferably 10 jim or more.
[0046]
Fig. 10 shows a cross-sectional view taken along the X-X
line of Fig. 9. The two arms 13a, 13b are formed on a substrate and the quarter wave plates 16a, 16b are provided to extend across cores of the respective arms 13a, 13b.
Fig. 10 shows a cross-sectional view taken along the X-X
line of Fig. 9. The two arms 13a, 13b are formed on a substrate and the quarter wave plates 16a, 16b are provided to extend across cores of the respective arms 13a, 13b.
[0047]
In contrast to the example shown in Fig. 2, in the waveguide-type polarization beam splitter of the embodiment, the wavelength dependence of the polarization extinction ratio is drastically reduced as shown in Fig. 11.
In contrast to the example shown in Fig. 2, in the waveguide-type polarization beam splitter of the embodiment, the wavelength dependence of the polarization extinction ratio is drastically reduced as shown in Fig. 11.
[0048]
Moreover, in contrast to the example shown in Fig. 3, in the waveguide-type polarization beam splitter of the embodiment, the polarization extinction ratio of 25dB or more is secured as shown in Fig. 12 in a case where the manufacturing tolerance is considered.
Reference Signs List
Moreover, in contrast to the example shown in Fig. 3, in the waveguide-type polarization beam splitter of the embodiment, the polarization extinction ratio of 25dB or more is secured as shown in Fig. 12 in a case where the manufacturing tolerance is considered.
Reference Signs List
[0049]
101, 11 Input optical waveguide 102, 12 First optical coupler 103, 13 Pair of optical waveguide arms 104, 15 waveguide groove 14, 17 Tapered optical waveguide or parabolic optical waveguide 105, 16 Quarter wave plate 106, 18 Second optical coupler 107, 19 Output optical waveguide 20 Clad 21 Core 22 Delay
101, 11 Input optical waveguide 102, 12 First optical coupler 103, 13 Pair of optical waveguide arms 104, 15 waveguide groove 14, 17 Tapered optical waveguide or parabolic optical waveguide 105, 16 Quarter wave plate 106, 18 Second optical coupler 107, 19 Output optical waveguide 20 Clad 21 Core 22 Delay
Claims (8)
1. A
waveguide-type polarization beam splitter formed on a substrate, characterized in that the waveguide-type polarization beam splitter comprises:
one or two input optical waveguides;
a first optical coupler optically coupled to the one or two input optical waveguides and having one input and two outputs or two inputs and two outputs;
a pair of optical waveguide arms optically coupled to the outputs of the first optical coupler, wherein the pair of optical waveguide arms includes a first optical waveguide arm and a second optical waveguide arm; and a second optical coupler optically coupled to the pair of optical waveguide arms and having two inputs and one output or two inputs and two outputs, wherein a groove is provided to extend across the pair of optical waveguide arms, two quarter wave plates are inserted in the groove to extend respectively across the pair of optical waveguide arms, and polarization axes of the respective two quarter wave plates are orthogonal to each other, one of the first optical coupler and the second optical coupler is an optical coupler which gives a phase shift of about 90° or about -900 between coupled or split light beams, and another one of the first optical coupler and the second optical coupler is an optical coupler which gives a phase shift of about 0° or about 180°
between coupled or split light beams, and a length of the first optical waveguide arm extending between the first and second optical couplers equals to a length of the second optical waveguide arm extending between the first and second couplers.
waveguide-type polarization beam splitter formed on a substrate, characterized in that the waveguide-type polarization beam splitter comprises:
one or two input optical waveguides;
a first optical coupler optically coupled to the one or two input optical waveguides and having one input and two outputs or two inputs and two outputs;
a pair of optical waveguide arms optically coupled to the outputs of the first optical coupler, wherein the pair of optical waveguide arms includes a first optical waveguide arm and a second optical waveguide arm; and a second optical coupler optically coupled to the pair of optical waveguide arms and having two inputs and one output or two inputs and two outputs, wherein a groove is provided to extend across the pair of optical waveguide arms, two quarter wave plates are inserted in the groove to extend respectively across the pair of optical waveguide arms, and polarization axes of the respective two quarter wave plates are orthogonal to each other, one of the first optical coupler and the second optical coupler is an optical coupler which gives a phase shift of about 90° or about -900 between coupled or split light beams, and another one of the first optical coupler and the second optical coupler is an optical coupler which gives a phase shift of about 0° or about 180°
between coupled or split light beams, and a length of the first optical waveguide arm extending between the first and second optical couplers equals to a length of the second optical waveguide arm extending between the first and second couplers.
2. The waveguide-type polarization beam splitter according to claim 1, characterized in that the optical coupler which gives the phase shift of about 0° or about 180° between coupled or split light beams is any one of a Y-branch coupler, a multimode interference optical coupler having one input and two outputs, a multimode interference optical coupler having two inputs and one output, and an X-branch coupler.
3. The waveguide-type polarization beam splitter according to claim 1 or 2, characterized in that the optical coupler which gives the phase shift of about 90° or about -90° between coupled or split light beams is a multimode interference optical coupler having two inputs and two outputs or a directional coupler.
4. The waveguide-type polarization beam splitter according to any one of claims 1 to 3, characterized in that angles of the polarization axes of the two quarter wave plates respectively form angles of 0° and 90° with respect to a substrate plane of the waveguides.
5. The waveguide-type polarization beam splitter according to any one of claims 1 to 4, characterized in that each of the two quarter wave plates is a polyimide wave plate.
6. The waveguide-type polarization beam splitter according to any one of claims 1 to 5 characterized in that the waveguide-type polarization beam splitter further comprises tapered portions before and after the groove.
7. The waveguide-type polarization beam splitter according to any one of claims 1 to 6, characterized in that the waveguide-type polarization beam splitter further comprises waveguide lenses before and after the groove.
8. The waveguide-type polarization beam splitter according to any one of claims 1 to 7, characterized in that each of the optical waveguides is a quartz-based optical waveguide formed on a silicon substrate.
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| JP2011014545 | 2011-01-26 | ||
| JP2011-014545 | 2011-01-26 | ||
| PCT/JP2012/000474 WO2012102039A1 (en) | 2011-01-26 | 2012-01-25 | Waveguide-type polarization beam splitter |
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| CA2825540A1 CA2825540A1 (en) | 2012-08-02 |
| CA2825540C true CA2825540C (en) | 2016-12-13 |
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| EP (1) | EP2669722B1 (en) |
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| US10132928B2 (en) | 2013-05-09 | 2018-11-20 | Quanergy Systems, Inc. | Solid state optical phased array lidar and method of using same |
| US10126412B2 (en) | 2013-08-19 | 2018-11-13 | Quanergy Systems, Inc. | Optical phased array lidar system and method of using same |
| JP2015219276A (en) * | 2014-05-14 | 2015-12-07 | 日本電信電話株式会社 | Polarization beam splitter circuit |
| US9753351B2 (en) * | 2014-06-30 | 2017-09-05 | Quanergy Systems, Inc. | Planar beam forming and steering optical phased array chip and method of using same |
| US9869753B2 (en) | 2014-08-15 | 2018-01-16 | Quanergy Systems, Inc. | Three-dimensional-mapping two-dimensional-scanning lidar based on one-dimensional-steering optical phased arrays and method of using same |
| JPWO2016060263A1 (en) * | 2014-10-17 | 2017-08-03 | 有限会社オートクローニング・テクノロジー | Integrated optical coupler with polarization separation / combination function |
| US10036803B2 (en) | 2014-10-20 | 2018-07-31 | Quanergy Systems, Inc. | Three-dimensional lidar sensor based on two-dimensional scanning of one-dimensional optical emitter and method of using same |
| US10641876B2 (en) | 2017-04-06 | 2020-05-05 | Quanergy Systems, Inc. | Apparatus and method for mitigating LiDAR interference through pulse coding and frequency shifting |
| KR20190115757A (en) | 2018-04-03 | 2019-10-14 | 한국전자통신연구원 | Optical circuit element |
| CN108761648B (en) * | 2018-06-04 | 2019-06-18 | 华中科技大学 | A kind of three ports light rings of hybrid integrated |
| GB2575653A (en) * | 2018-07-17 | 2020-01-22 | Univ College Cork National Univ Of Ireland | Phase modulator for optical signal using multimode interference couplers |
| CN110646884B (en) * | 2019-07-09 | 2021-01-26 | 华中科技大学 | Polarization beam splitter with large manufacturing tolerance and high polarization extinction ratio |
| KR20210018726A (en) | 2019-08-09 | 2021-02-18 | 한국전자통신연구원 | Coherent optical receiver and fabricating method thereof |
| US11474298B2 (en) * | 2020-11-17 | 2022-10-18 | Intel Corporation | 2×2 optical unitary matrix multiplier |
| US11251876B2 (en) | 2020-11-17 | 2022-02-15 | Intel Corporation | Optical analog matrix multiplier for optical neural networks |
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| JP2614365B2 (en) | 1991-01-14 | 1997-05-28 | 日本電信電話株式会社 | Polarization-independent waveguide optical device |
| JP3501235B2 (en) * | 1993-05-07 | 2004-03-02 | 日本電信電話株式会社 | Waveguide type optical device |
| JPH1130766A (en) | 1997-07-09 | 1999-02-02 | Nippon Telegr & Teleph Corp <Ntt> | Optical non-reciprocal circuit |
| JP3502578B2 (en) | 1999-08-11 | 2004-03-02 | 日本電信電話株式会社 | Waveguide type polarization state measuring instrument |
| JP3527455B2 (en) | 2000-03-09 | 2004-05-17 | 日本電信電話株式会社 | Optical signal processing device |
| GB0124840D0 (en) | 2001-10-16 | 2001-12-05 | Univ Nanyang | A polarization beam splitter |
| JP4405978B2 (en) | 2006-04-18 | 2010-01-27 | 日本電信電話株式会社 | Optical signal processor |
| EP2653899B1 (en) | 2007-01-10 | 2016-06-22 | Nippon Telegraph And Telephone Corporation | Waveguide type optical interference circuit |
| CN101784926B (en) | 2007-08-24 | 2012-05-16 | 日本电信电话株式会社 | Polarized wave-independent waveguide type optical interferometric circuit |
| US8787710B2 (en) | 2009-06-02 | 2014-07-22 | Nippon Telegraph And Telephone Corporation | Wideband interferometer type polarization light beam combiner and splitter |
| WO2011027895A1 (en) * | 2009-09-07 | 2011-03-10 | 古河電気工業株式会社 | Plc type demodulator and optical transmission system |
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2012
- 2012-01-25 CA CA2825540A patent/CA2825540C/en active Active
- 2012-01-25 WO PCT/JP2012/000474 patent/WO2012102039A1/en active Application Filing
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| JP5567696B2 (en) | 2014-08-06 |
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| EP2669722A4 (en) | 2014-02-19 |
| EP2669722A1 (en) | 2013-12-04 |
| US20130301976A1 (en) | 2013-11-14 |
| EP2669722B1 (en) | 2015-01-14 |
| WO2012102039A1 (en) | 2012-08-02 |
| JPWO2012102039A1 (en) | 2014-06-30 |
| CA2825540A1 (en) | 2012-08-02 |
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